1. Field of the Invention
The present invention relates to recording apparatuses, particularly to a technique to display, by OSD (On Screen Displays), GUI (Graphical User Interface) screens that are unique to recording apparatuses.
2. Description of the Related Art
Some recording apparatuses show the operational state they are in with the use of a technique called OSD, which is to display, on a display device connected thereto, a GUI screen unique to each recording apparatus.
The Japanese Unexamined Patent Application Publication No. 10-191463 discloses a technique to have one device display a screen for controlling another device when a plurality of devices are connected with each other via a network such as a LAN.
A conventional recording apparatus for recording analogue broadcast is able to perform OSD by superimposing GUI screen data of analogue signals on video data which are analogue signals according to the NTSC (National Television System Committee) method or the like, and transmitting them to a display device. As for digital broadcast, however, encoded digital signals are used as video data; therefore, a recording apparatus is not able to simply superimposing GUI screen data on video data which are encoded digital signals.
In order to display, by OSD, by superimposing an image unique to the recording apparatus on video data which are encoded digital signals, it is required to decode the encoded video data, and further to convert digital signals into analogue signals, and then to superimpose the image unique to the recording apparatus on the video data of analogue signals.
Display devices including digital TVs that are able to decode encoded video data have become popular, however. If display devices have built-in decoders, recording apparatuses do not need to have built-in decoders and their prices can stay low. Recording apparatuses tend to specialize in a function as a streamer which is to record (accumulate) video data received via digital broadcast and transmit the data while having them remain as digital data to a display device via a cable in accordance with the IEEE 1394 standard, which is for digital connections.
Recording apparatuses that do not include a decoder therein have a problem of not being able to use a technique to decode encoded digital signals and superimpose a GUI screen unique to each recording apparatus.
Further, as for digital broadcast, data broadcast is offered along with video data broadcast, and also a plurality of pieces of video data are multiplexed and broadcasted. Such video data have a data structure that allows a link between video and data broadcast, as well as multi-view programs which are peculiar to digital broadcast. When video data are converted to analogue signals, such data structures will be unavailable. If analogue signals are transmitted to a display device without such a data structure, there is a problem that the display device is not able to offer multi-view programs and the like.